Heretofore, a technology for diagnosing and treating an organ of a patient, such as a large intestine or a stomach, using a real endoscopic image captured by an endoscope inserted in the organ has been known. Further, a technology for generating a virtual endoscopic image from a three-dimensional volume image obtained by CT imaging or the like and displaying the generated image has also been known.
Japanese Unexamined Patent Publication No. 2006-061274 proposes a method in which the position and orientation of an endoscope inserted into an organ are detected, then a virtual endoscopic image having the same field of view as the real endoscopic image is generated based on the detected position and orientation, and the real endoscopic image obtained by the endoscope is texture mapped to the virtual endoscopic image, whereby an image for display is generated.